@blackEyEz, I don't think it is MediaStream in particular, MediaPortal 1.0.x has trouble with UAC in Vista (that's my experience anyway). In 1.1 alpha they're making it UAC friendly I believe. Haven't tried it yet because the skins and plugins go to new directories and I believe the skin needs to be compatible (could be wrong on that one).
MediaStream is running fine on 1.0.2 here. Try clearing the cache folder, or deleting your current config (mediaportal.xml). As long as you make a backup beforehand and keep the database and thumbs folders intact (because losing those would seriously suck). nothing should go wrong.
Thank you for replying i turned UAC off and cleared cache and the exception is gone *phew*
Now i have the next problem, i used the plugin preference of mediastream to create my menu and still i get a this screen:
How do i solve this?